Diagnosis of thromboembolic disease during infancy and childhood.

Thromboembolic disorders are frequent complications in pediatric patients and the incidence seems to rise. Adult guidelines for thromboembolism do not hold for children because there are many age-related features. Congenital prethrombotic disorders play a major role in the pediatric population and activated protein C (APC) resistance is also the most frequently encountered problem. Acquired risk factors in children are central venous line thrombosis with serious complications, cardiac diseases such as cardiomyopathies, prosthetic heart valves and aneurysms, renal vein thrombosis, and nephrotic syndrome. Renal vein thrombosis primarily affects newborns. Children with the antiphospholipid antibody syndrome also have thromboses although less frequent than adults, but systemic lupus erythematosus is associated with a high incidence. Acute lymphoblastic leukemia is frequently associated with thrombosis in children, especially when complicated by APC resistance. The greatest risk of thrombosis in children is during the neonatal period, and again congenital prethrombotic states and catheter placement play a major role. The clinical manifestations in children reflect the site of the thrombosis and extensive laboratory evaluations and advanced diagnostic procedures must be employed to diagnose the thrombotic events.